Method of backing electrotypes.



THOMAS WEBSTER,` or -NEW YORK, 'i\i. Y.

' METHOD iOIF BACKING ELECTRQTYPES.

Original.appiicatnr'led June 24, l1915,

j To all fio/wm it may concern:

Be it known ,that I, THOMAS .WEsrEii, a citizen of the United States ofAmerica, and a resident ofNeW York, in the4 borough of Brooklyn, countyof Kings,l and State of New York7 have'invented certain' new and usefulImprovements iii Methods of Backing Electrotypes, whereof the followingis a specification.

In the methods of backingelectrotypes as heretofore practised, the shellforming the lbody of the electrotype after removal from .theelectrolytic bath is cleaned and placed face downward on a backing panwhich has a very smooth surface. Then a liquid'backing` metal is pouredoverthe shell in the panto a depth required for the thickness of thebacking d'esired. Then the pan and its contents are subjected .to acooling operation which solidifies the molten ymetal around the shelland forms the backing therefor. This cooling-operation usually consistsin expos ing the pari and its contents to an ordinary temperature for asufficient tini'e'ofvsayfrom twenty-five minutes to half an hour, or insubjecting the pan and its contents to a blast of air froma` blowerwhereby the time of cooling is reduced to say five minutes more or less.But in both these methods of cooling the metal of the backing shrinksmore or less unequally from the pan and causes irregularities on the'printing surface of the electrotype plate,' \vhioh irregularities mustbe corrected by a finishing operation before the plate can be deliveredin a condition acceptable to the user. This finishing is an expensiveand time consuming` step.

The objects of this invention are to shorten the cooling step and toperform it in such manner as to avoid the inequalities referred to anddo away With the leveling operation usually required afterthe coolingoperation is completed. j i I' In carrying out this invention iii-itspre-l ferred form, the pan containing the shell and the backing materialcovering it, is subjected to chilling material applied to the bottomthereof, preferably in the form of an absorbent pad saturated withWater. This effects a sudden chilling of the bottom of the lp an andthecold passes by conduction therethrough and touches the shell and thebacking material surrounding it'on the lower face thereof and Causes allparts` of the vcase to shrink toward the pan, andthe WeightSpecification of Letters Patent,

Patented Oct. 31, 1916.

ofthe hot molten metal above the shell I serves to press the face of thelatter against the pan. 'Under this cooling operation an electrotype isproduced quicklyand Without inequalities on its printing face. In theaccompanying drawings, .which illustrate a convenient apparatus, forcarry.-

ing outthis process, Figure 1 represents a.-

side elevation partly in section of a backing panand cooling pan,theformer con-v taining the shell and backing` material and the lattercontaining the cooling pad in position preparatory to effecting thecooling operation. Fig.-2 represents a longitudinalsection ofthe pans inoperative position foi cooling, the cooling pad being in vcontact 4withlthe bottom of the backing pan.- Fig; 3

represents a modified forni of the apparatus in which the coolingmaterial consists of the water in the cooling pan, thel pad beingomitted.

sponding parts in the different figures.

The method may be carried out by an api I paratus comprising abackingfpan l0 for containing the electrolytic shell and the A. Similarreference numbers indicate correbacking material, a cooling pan 20 forcontaining the cooling material and means for shiftingone of said pansto place the bottom of the backing pan in`contact with the coolingmaterial in the cooling pan. The backing pan l0 is supported bysuspension rods l1 or otherwise and has the upper face of its bottomsmoothed in the usual manner and the underface thereof exposed ,forcontact 'with the'cooling materialifi thecooling pan.

The cooling pan 20, which carries cooling material for contact with thebottom of the and a current may beA maintained through I the pan and thepad mounted therein.

One of the pansis moved by any suitablef means to cause the coolingmaterial inthe cooling pan tol contact with the backing pair. n

The means shown includes a rock shaft 30, arms 31 and 32 fixed thereto,lifting levers 33 and 34 engaging` the cooling pan, links 35 and 36connecting said arms with said levers and an actuating lever 37 attachedto said shaft. l l

In carryingout by meansof this apparatus the cooling step `in thebacking method,

the shell 40 of the electrotype is placedl with its printing facedownward incontact with the upper face ofthe bottom of the backing pan10Aand the usual molten metal I45 is poured into said pan, covering saidshell,

and the weight'of said Ainetalover the shell presses the latter downagainst the bottom of the pan. `Th cooling pan Q0 is then` the absorbentpad 25. The hot backing panr coming in contact with the wet cooling padcauses more or less evaporation or vaporization of the water, whichincreases the coolino' effect. lVater is supplied through the inlet totake the place of that evaporated.

QThe quantity of water maintained in" the cooling pan is such Ithat thepad is thoroughly ksaturated therewith, but the water does not form alayer above the surface of the pad under normal conditions.

The. pad 25 may be omitted if desired as shown in Fig. 3. In thatcasethe water or other evaporative liquid' supplied to the cooling box comesbodily intocontact with the bottom of the backing pan containing theshell and backing metal to be cooled; but 'I find it preferableinpractice to bring the evaporative liquid into contact 'with the bottomof the backing pan through-the capillary action of the pad. This isprobably due to the fact that the lpad distributes the evaporativeliquid to the bottoml of the backing pan through capillary action andpermits the passage of air between the fibers of the pad and increasesthe evaporation of the liquid and thereby intensifies the coolingeffect; Y

The advantages of this method of cooling by water contact andevaporation-are that the sudden chilling by conduction through thebottom of the backing pan of the face of the casting causesthe metal 'asit cools toshrink toward and into contact with the upper face of thebacking pan, the plates being all shrunk alike and the faces thereofdrawn down flat, doing Vaway with straightening iii many cases,especiallyon type and halftones, providing the .backing pan is smoothtinuously moistened felt pad, the casts are i f cooled off in rfortyseconds. Thus the capacity of a plant is enlarged and at the saine timethe product is improved and the eX-l pense of a.. blower is eliminated'.

This case is a division of my apparatus 'application Serial No. 36,148filed June 24, 1915. K

I claim as my'invention:

1. The method of backingy electrotypes which consists in'placing thesolid shell face downward in Contact with the upper face of the metallicbottom of a backing pan, pouring molten backing metal in said pan to adepth which covers said shell, ,and subjectl ing at once the whole areaof the'ybottom of said pan while said solid and liquid metals arel intouch therewith to uniform contact with an evaporative cooling liquid. i2. The method of backing electrotypes which consists in placing theyshell face downward in contact with the upper face of the metallicbottom of a backing Jan, pouring molten backing metal in'sai pan to adepth which' covers said shell,l and subjecting the bottom of said panto contact with an absorbent pad containing an evaporative coolingliquid;

3. The method of .backing electrotypes which consists in placing theshell face downward in contact with the upper face of the metallicbottom of a backingk an, pouring' molten `backing metal in lsai pan to adepth which covers said shell, and subject-y ing the bottom of said panto contact with an-absorbent pad composed of felt and containing anevaporatiw, cooling li uid.

4. That step in the art of backing electrotypes which consists insubjecting the botv tom of afbacking pan containing thev solid 100 shelland the molten 'backing metal while both touch saidbottom to uniformcontact over itswhole area with a coolin evaporative liquid; .wherebythe face of t e electrotype only isfsubjected to a chilling operation105 causing the metalto ,shrink'towardthe pan and avoidingirregularities on theface of the electroty e. f

Intestimony thatclaim the foregoing as my inventionyl have signed myname in 11/0 presence of two subscribing witnesses. l

' `THOMAS WEBSTER. Witnesses: i 4

l). Lewis MATTERN, A C. P. GOEPEL.

